<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>$mount</title>
    <script src="/vue.js"></script>
  </head>
  <body>
    <div id="app">
      <h2>{{msg}}</h2>
    </div>
    <script>
      const vm = new Vue({
        data: {
          msg: "$mount",
        },
      });

      /* 我们可以 Vue 的挂载时机，其他和 el 机泵相同 */
      setTimeout(() => {
        vm.$mount("#app");
      }, 1000)
    </script>
  </body>
</html>
